Integrated method and apparatus for treatment of produced water

Abstract

Integrated processes for the treatment of produced water, including for example treatment in connection with hydrocarbon production operations using bulk solid-liquid separation, organics removal, and desalination by osmotically assisted reverse osmosis (OARO) and/or vacuum membrane distillation (VMD). Various pretreatment technologies including without limitation pH adjustment, oxidant addition, particle removal, oxidant removal, followed by OARO and/or VMD, may be combined with a subsequent polishing process of the desalinated produced water such as to remove ammonia, boron, heavy metals, and/or organics. Water to be treated may be produced water that has been pumped from a subterranean reservoir. The treated water may be sent for beneficial reuse which includes without limitation different fit-for purpose applications including those outside oil and gas industry at a low cost.

The invention claimed is: 
     
         1 . An integrated process to treat produced water generated during oil and gas production, comprising the steps of:
 (a) obtaining produced water from an oil and/or gas producing well, water transfer pipeline or salt-water disposal well, wherein the produced water includes: heavy metals, oil and grease, water soluble organics, colloidal and suspended solids, and 5,000 to 300,000 ppm of total dissolved solids;   (b) treating the produced water of step “a” by   (i) adding an oxidizer selected from the group consisting of: oxygen, hydrogen peroxide, chlorine, bromine, bleach, ClO 2 , peracetic acid, and combinations thereof;   and/or   (ii) subjecting the produced water of step “a” to a treatment selected from the group consisting of: ozone, UV, hydroxyl free radicals, and combinations thereof;   (c) using a microfiltration system to treat the produced water of step “b” until the produced water satisfies each of the following plurality of specified treatment levels:   heavy metals less than 10 ppm,   oil and grease less than 100 ppm,   water-soluble organics less than 100 ppm,   suspended solids less than 50 ppm, and   total dissolved solids less than 80% of the total dissolved solids in step “a”;   wherein the microfiltration system includes a membrane coating having a regenerable surface layer selected from the group consisting of: metal oxide powder, aluminosilicates, aluminum oxides, iron oxides, powdered activated carbon, clays, polymeric sorbents, catalysts, and combinations thereof;   (d) creating a pretreated water stream from the produced water of step “c” by passing it through a packed bed or fluidized bed vessel containing media selected from the group consisting of: granulated activated carbon, metal-organic frameworks, covalent organic frameworks, clays, polymeric sorbents, and combinations thereof thereby decreasing water-soluble organics;   (e) creating a first volume of pretreated water by sending the pre-treated water stream of step “d” to a pre-treatment water storage tank wherein the storage tank is fluidly connected to the packed bed or fluidized bed vessel; and   (f) using osmotically assisted reverse osmosis (“OARO”) and/or vacuum membrane distillation (“VMD”) to treat a second volume of water from the pre-treatment water storage tank thereby further decreasing levels of total dissolved solids to less than 1000 ppm, and creating at least two output streams selected from the group consisting of:   a first concentrated water stream,   a second concentrated water stream,   a first desalinated water stream,   a second desalinated water stream,   a first precipitated solids stream,   a second precipitated solids stream, and   combinations thereof,   wherein the OARO treatment further comprises an osmotically assisted cascade concentrator and water desalination system that creates at least   a first dilute draw stream using a first OARO stage,   at least a second dilute draw stream using a second OARO stage,   a desalinated stream using reverse osmosis from the first dilute draw stream and the second dilute draw stream, and   a reject stream from the second OARO stage.   
     
     
         2 . An integrated process to treat produced water generated during oil and gas production, comprising the steps of:
 (a) obtaining produced water from an oil and/or gas producing well, water transfer pipeline or salt-water disposal well, wherein the produced water includes: heavy metals, oil and grease, water soluble organics, colloidal and suspended solids, and 5,000 to 300,000 ppm of total dissolved solids;   (b) treating the produced water of step “a” by   (i) adding an oxidizer selected from the group consisting of: oxygen, hydrogen peroxide, chlorine, bromine, bleach, ClO 2 , peracetic acid, and combinations thereof;   and/or   (ii) subjecting the produced water of step “a” to a treatment selected from the group consisting of: ozone, UV, hydroxyl free radicals, and combinations thereof;   (c) using a microfiltration system to treat the produced water of step “b” until the produced water satisfies each of the following plurality of specified treatment levels:   heavy metals less than 10 ppm,   oil and grease less than 100 ppm,   water-soluble organics less than 100 ppm,   suspended solids less than 50 ppm, and   total dissolved solids less than 80% of the total dissolved solids in step “a”;   wherein the microfiltration system includes a membrane coating having a regenerable surface layer selected from the group consisting of: metal oxide powder, aluminosilicates, aluminum oxides, iron oxides, powdered activated carbon, clays, polymeric sorbents, catalysts, and combinations thereof;   (d) creating a pretreated water stream from the produced water of step “c” by passing it through a packed bed or fluidized bed vessel containing media selected from the group consisting of: granulated activated carbon, metal-organic frameworks, covalent organic frameworks, clays, polymeric sorbents, and combinations thereof thereby decreasing water-soluble organics;   (e) creating a first volume of pretreated water by sending the pre-treated water stream of step “d” to a pre-treatment water storage tank wherein the storage tank is fluidly connected to the packed bed or fluidized bed vessel; and   (f) using osmotically assisted reverse osmosis (“OARO”) and/or vacuum membrane distillation (“VMD”) to treat a second volume of water from the pre-treatment water storage tank thereby further decreasing levels of total dissolved solids to less than 1000 ppm, and creating at least two output streams selected from the group consisting of:   a first concentrated water stream,   a second concentrated water stream,   a first desalinated water stream,   a second desalinated water stream,   a first precipitated solids stream,   a second precipitated solids stream, and   combinations thereof,   wherein creating the generated second stream of desalinated water from the treatment selected from the VMD in step “f” further comprises removing water vapor having ammonia and volatile organics, wherein said water vapor is passed through a sorbent bed having a plurality of sorbents arranged in series to remove said ammonia and volatile organics.   
     
     
         3 . An integrated process to treat produced water generated during oil and gas production, comprising the steps of:
 (a) obtaining produced water from an oil and/or gas producing well, water transfer pipeline or salt-water disposal well, wherein the produced water includes: heavy metals, oil and grease, water soluble organics, colloidal and suspended solids, and 5,000 to 300,000 ppm of total dissolved solids;   (b) treating the produced water of step “a” by   (i) adding an oxidizer selected from the group consisting of: oxygen, hydrogen peroxide, chlorine, bromine, bleach, peracetic acid, ClO 2 , and combinations thereof;   and/or   (ii) subjecting the produced water of step “a” to a treatment selected from the group consisting of: ozone, UV, hydroxyl free radicals, and combinations thereof;   (c) using a microfiltration system to treat the produced water of step “b” until the produced water satisfies each of the following plurality of specified treatment levels:   heavy metals less than 10 ppm,   oil and grease less than 100 ppm,   water-soluble organics less than 100 ppm,   suspended solids less than 50 ppm, and   total dissolved solids less than 80% of the total dissolved solids in step “a”;   wherein the microfiltration system includes a membrane coating having a regenerable surface layer selected from the group consisting of: metal oxide powder, aluminosilicates, aluminum oxides, iron oxides, powdered activated carbon, clays, polymeric sorbents, catalysts, and combinations thereof;   (d) creating a pretreated water stream from the produced water of step “c” by passing it through a packed bed or fluidized bed vessel containing media selected from the group consisting of: granulated activated carbon, metal-organic frameworks, covalent organic frameworks, clays, polymeric sorbents, and combinations thereof thereby decreasing water-soluble organics;   (e) creating a first volume of pretreated water by sending the pre-treated water stream of step “d” to a pre-treatment water storage tank wherein the storage tank is fluidly connected to the packed bed or fluidized bed vessel; and   (f) using osmotically assisted reverse osmosis (“OARO”) and/or vacuum membrane distillation (“VMD”) to treat a second volume of water from the pre-treatment water storage tank thereby further decreasing levels of total dissolved solids to less than 1000 ppm, and creating at least two output streams selected from the group consisting of:   a first concentrated water stream,   a second concentrated water stream,   a first desalinated water stream,   a second desalinated water stream,   a first precipitated solids stream,   a second precipitated solids stream, and   combinations thereof, wherein the generated second stream of desalinated water from the treatment selected from the VMD in step “f” is combined with the generated first stream of desalinated water from the treatment selected from the OARO in step “f” to generate a third stream of desalinated water with reduced level of volatile organics and ammonia.   
     
     
         4 . An integrated process to treat produced water generated during oil and gas
 production, comprising the steps of:   (a) obtaining produced water from an oil and/or gas producing well, water transfer pipeline or salt-water disposal well, wherein the produced water includes: heavy metals, oil and grease, water soluble organics, colloidal and suspended solids, and 5,000 to 300,000 ppm of total dissolved solids;   (b) treating the produced water of step “a” by   (i) adding an oxidizer selected from the group consisting of: oxygen, hydrogen peroxide, chlorine, bromine, bleach, peracetic acid, ClO 2 , and combinations thereof;   and/or   (ii) subjecting the produced water of step “a” to a treatment selected from the group consisting of: ozone, UV, hydroxyl free radicals, and combinations thereof;   (c) using a microfiltration system to treat the produced water of step “b” until the produced water satisfies each of the following plurality of specified treatment levels:   heavy metals less than 10 ppm,   oil and grease less than 100 ppm,   water-soluble organics less than 100 ppm,   suspended solids less than 50 ppm, and   total dissolved solids less than 80% of the total dissolved solids in step “a”;   wherein the microfiltration system includes a membrane coating having a regenerable surface layer selected from the group consisting of: metal oxide powder, aluminosilicates, aluminum oxides, iron oxides, powdered activated carbon, clays, polymeric sorbents, catalysts, and combinations thereof;   (d) creating a pretreated water stream from the produced water of step “c” by passing it through a packed bed or fluidized bed vessel containing media selected from the group consisting of: granulated activated carbon, metal-organic frameworks, covalent organic frameworks, clays, polymeric sorbents, and combinations thereof thereby decreasing water-soluble organics;   (e) creating a first volume of pretreated water by sending the pre-treated water stream of step “d” to a pre-treatment water storage tank wherein the storage tank is fluidly connected to the packed bed or fluidized bed vessel; and   (f) using osmotically assisted reverse osmosis (“OARO”) and/or vacuum membrane distillation to treat a second volume of water from the pre-treatment water storage tank thereby further decreasing levels of total dissolved solids to less than 1000 ppm, and creating at least two output streams selected from the group consisting of:   a first concentrated water stream,   a second concentrated water stream,   a first desalinated water stream,   a second desalinated water stream,   a first precipitated solids stream,   a second precipitated solids stream, and   combinations thereof, wherein the generated stream of desalinated water from the treatment selected from the VMD in step “f” is cooled to less than 40 C using a heat exchanger, further comprising adjusting said cooled desalinated water to a pH in the range of 6.0 to 8.0 by feeding an acid or base through a feeding pump connected to the heat exchanger, and processing said desalinated water with the adjusted pH through a treatment selected from the group consisting of OARO, RO, and combinations thereof to generate a fourth stream of desalinated water with a reduced level of volatile organics and ammonia.   
     
     
         5 . The process of  claim 4 , wherein in step (f) an acid is fed through the feeding pump and the acid is selected from the group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, citric acid and combinations thereof. 
     
     
         6 . The process of  claim 4 , wherein in step (f) a base is fed through the feeding pump and the base is selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide, and combinations thereof. 
     
     
         7 . An integrated process to treat produced water generated during oil and gas production, comprising the steps of:
 (a) obtaining produced water from an oil and/or gas producing well, water transfer pipeline or salt-water disposal well, wherein the produced water includes: heavy metals, oil and grease, water soluble organics, colloidal and suspended solids, and 5,000 to 300,000 ppm of total dissolved solids;   (b) treating the produced water of step “a” by   (i) adding an oxidizer selected from the group consisting of: oxygen, hydrogen peroxide, chlorine, bromine, bleach, ClO 2 , peracetic acid, and combinations thereof;   and/or   (ii) subjecting the produced water of step “a” to a treatment selected from the group consisting of: ozone, UV, hydroxyl free radicals, and combinations thereof;   (c) using a microfiltration system to treat the produced water of step “b” until the produced water satisfies each of the following plurality of specified treatment levels:   heavy metals less than 10 ppm,   oil and grease less than 100 ppm,   water-soluble organics less than 100 ppm,   suspended solids less than 50 ppm, and   total dissolved solids less than 80% of the total dissolved solids in step “a”;   wherein the microfiltration system includes a membrane coating having a regenerable surface layer selected from the group consisting of: metal oxide powder, aluminosilicates, aluminum oxides, iron oxides, powdered activated carbon, clays, polymeric sorbents, catalysts, and combinations thereof;   (d) creating a pretreated water stream from the produced water of step “c” by passing it through a packed bed or fluidized bed vessel containing media selected from the group consisting of: granulated activated carbon, metal-organic frameworks, covalent organic frameworks, clays, polymeric sorbents, and combinations thereof thereby decreasing water-soluble organics;   (e) creating a first volume of pretreated water by sending the pre-treated water stream of step “d” to a pre-treatment water storage tank wherein the storage tank is fluidly connected to the packed bed or fluidized bed vessel; and   (f) using osmotically assisted reverse osmosis (“OARO”) and/or vacuum membrane distillation (“VMD”) to treat a second volume of water from the pre-treatment water storage tank thereby further decreasing levels of total dissolved solids to less than 1000 ppm, and creating at least two output streams selected from the group consisting of:   a first concentrated water stream,   a second concentrated water stream,   a first desalinated water stream,   a second desalinated water stream,   a first precipitated solids stream,   a second precipitated solids stream, and   combinations thereof, wherein the OARO treatment further comprises:   (i) treating the second volume of water in first and second RO units, wherein the first RO unit has a first RO input and creates a first RO concentrate stream and a first RO permeate stream, and the second RO unit has a second RO input and creates a second RO concentrate stream and second RO permeate stream,   (ii) wherein the second RO permeate stream is selectively fluidly connected to the first RO input and wherein the second RO concentrate stream is selectively fluidly connected to the second RO permeate stream.   
     
     
         8 . The process of  claim 7 , comprising treating the second volume of water in each of the OARO and VMD units, the units being selectively configurable in series or parallel. 
     
     
         9 . The process of  claim 7 , wherein step “f” further comprises treating the second volume of water in a VMD unit having a VMD input and creating a VMD concentrate stream and a VMD permeate stream, wherein the VMD concentrate stream is fluidly connected to the VMD input. 
     
     
         10 . An integrated process to treat produced water generated during oil and gas production, comprising the steps of:
 (a) obtaining produced water from an oil and/or gas producing well, water transfer pipeline or salt-water disposal well, wherein the produced water includes: heavy metals, oil and grease, water soluble organics, colloidal and suspended solids, and 5,000 to 300,000 ppm of total dissolved solids;   (b) treating the produced water of step “a” by   (i) adding an oxidizer selected from the group consisting of: oxygen, hydrogen peroxide, chlorine, bromine, bleach, ClO 2 , peracetic acid, and combinations thereof;   and/or   (ii) subjecting the produced water of step “a” to a treatment selected from the group consisting of: ozone, UV, hydroxyl free radicals, and combinations thereof;   (c) using a microfiltration system to treat the produced water of step “b” until the produced water satisfies each of the following plurality of specified treatment levels:   heavy metals less than 10 ppm,   oil and grease less than 100 ppm,   water-soluble organics less than 100 ppm,   suspended solids less than 50 ppm, and   total dissolved solids less than 80% of the total dissolved solids in step “a”;   wherein the microfiltration system includes a membrane coating having a regenerable surface layer selected from the group consisting of: metal oxide powder, aluminosilicates, aluminum oxides, iron oxides, powdered activated carbon, clays, polymeric sorbents, catalysts, and combinations thereof;   (d) creating a pretreated water stream from the produced water of step “c” by passing it through a packed bed or fluidized bed vessel containing media selected from the group consisting of: granulated activated carbon, metal-organic frameworks, covalent organic frameworks, clays, polymeric sorbents, and combinations thereof thereby decreasing water-soluble organics;   (e) creating a first volume of pretreated water by sending the pre-treated water stream of step “d” to a pre-treatment water storage tank wherein the storage tank is fluidly connected to the packed bed or fluidized bed vessel; and   (f) using osmotically assisted reverse osmosis (“OARO”) and/or vacuum membrane distillation (“VMD”) to treat a second volume of water from the pre-treatment water storage tank thereby further decreasing levels of total dissolved solids to less than 1000 ppm, and creating at least two output streams selected from the group consisting of:   a first concentrated water stream,   a second concentrated water stream,   a first desalinated water stream,   a second desalinated water stream,   a first precipitated solids stream,   a second precipitated solids stream, and combinations thereof,   wherein the OARO and VMD treatment further comprises:   (i) treating the second volume of water in first and second RO units, wherein the first RO unit has a first RO input and creates a first RO concentrate stream and a first RO permeate stream, and the second RO unit has a second RO input and creates a second RO concentrate stream and second RO permeate stream,   (ii) wherein the second RO permeate stream is selectively fluidly connected to the first RO input and wherein the second RO concentrate stream is selectively fluidly connected to the second RO permeate stream,   (iii) a VMD unit having a VMD input and creating a VMD concentrate stream and a VMD permeate stream, wherein   (iv) the VMD permeate stream is selectively fluidly connected to both the VMD input and the first RO input.   
     
     
         11 . The process of  claim 10 , wherein the first RO permeate stream is combined with the VMD permeate stream. 
     
     
         12 . The process of  claim 10 , wherein the second RO concentrate stream has solids and these solids are treated with a treatment unit selected from the group consisting of: filter, centrifuge, hydrocyclone, and combinations thereof.